Which of the following is NOT correct regarding the biosynthesis of purines and pyrimidines?

A) 5-phosphoribosyl-1-pyrophosphate (PRPP) is a precursor to both purines and pyrimidines.
B) The pyrimidine ring is synthesized first and then linked to 5-phosphoribosyl-1-pyrophosphate.
C) The purine ring is built around the C1 of 5-phosphoribosyl-1-pyrophosphate.
D) Both purines and pyrimidines use inosine monophosphate as a precursor.
E) Both purines and pyrimidines are built by adding carbon components to ribose 5-phosphate.